Possible Clues:

• 747 competitor
• Jet similar to a 747
• 1971 American Airlines debut
• Many a FedEx plane
• McDonnell Douglas jet
• FedEx flyer
• Jet airliner model that's an apt alternate title for this puzzle
• It made its last commercial flight in February 2014
• Airbus A300 alternative
• Classic McDonnell Douglas aircraft